白內障手術傷口大小及眼球結構對手術誘發散光之
研究

散光是由於角膜的曲率在兩主經軸不相等造成屈光不正，近年來由於手術中所使用的功能性水晶體可以矯正既有散光，大幅提高手術後病患的滿意度，然而白內障手術本身會造成角膜散光，可能抵銷水晶體對散光的矯正效果，因此本研究想找到造成手術角膜散光的影響因子。本研究病患眼睛自2004年至2011年於亞東紀念醫院進行同軸超音波晶體乳化術及植入人工水晶體總共842眼，我們依傷口尺寸及手術中所使用的水晶體植入器將病患分成四組，分別為2.2mm(cartridge D，Monarch III，N=248)、2.75mm(cartridge C，Monarch II，N=357；cartridge B，Monarch II，N=116)、3.2mm (folding forceps，no injector，N=121)，並個別表示成2.2mm+MIIID、2.75mm+MIIB、2.75mm+MIIC、3.2mm+no injector，平均年齡分別為70±11、68±11、66±12、69±10歲，手術位置為上側角膜緣(limbus)，傷口為三平面(three planes)。術前利用自動驗光儀(Topcon KR 8900)及非接觸式眼壓計(Topcon CT80)量測四組病患角膜曲率、眼壓(IOP)，並利用Zeiss IOL Master量測2.2mm(cartridge D，Monarch III)及2.75mm(cartridge C，Monarch II)之眼軸長(AxL)、前房深度(ACD)，術後一天、一週、一個月、兩個月、三個月量測四組之角膜曲率及眼壓，最後利用Alpin向量分析法來計算術後誘發散光(SIA)。術後針對不同傷口大小的SIA做差異性分析及術前散光、角膜曲率、ACD、AxL、Age與SIA做相關性分析。結果顯示2.2mm+MIIID組術後一週之SIA與2.75mm+MIIC、2.75mm+MIIB、3.2mm+no injector組有顯著差異（p<0.05），SIA分別為0.56±0.40 diopter (D)、0.71±0.68D、0.75±0.54D、0.80±0.63D。術後三個月之SIA分別為0.57±0.45D、0.58±0.55D、0.52±0.41D、0.54±0.33D，且傷口尺寸降到2.2mm時，SIA及眼壓在術後可提早穩定。除了尺寸造成的影響，結果亦顯示2.75mm+MIIC及2.2mm+MIIID組在術前具有高度散光、年紀比較大及前房深度較淺之病患術後會造成比較大之SIA。然而2.75mm組之病患在術前具有比較短的眼軸長及較低的眼壓會造成比較大的SIA。因此降低上側角膜緣傷口尺寸，不僅可達到不錯的術後效果，亦可考慮除了角膜散光以外的影響參數，能更精確預測SIA及計算人工水晶體度數以達最佳化。

關鍵字

手術誘發散光；屈光度；眼內壓；前房深度；眼軸長；角膜緣

並列摘要

Astigmatism is an optical defect in which vision is blurred due to the inability of the optics of the eye to focus a point object into a sharp focused image on the retina. Astigmatism correcting intraocular lens is an advanced technology product capable of correcting pre-existing corneal astigmatism, which increased postoperative visual quality and patient satisfaction in recent years. However, corneal incision in cataract surgery may induce certain amount of corneal astigmatism after surgery. The purpose of this study was to find the factors contributing to surgically induced corneal astigmatism. This retrospective study included 842 eyes acquired between 2004 and 2011 from Far Eastern Memorial Hospital following 2.2mm (cartridge D, Monarch III, N=248), 2.75mm (cartridge C, Monarch II, N=357; cartridge B, Monarch II, N=116), and 3.2mm (folding forceps, no injector, N=121) sized superior limbal incision phacoemulsification. The eyes were divided into four groups according to the corneal incision size and the cartridge used for intraocular lens insertion, namely 2.2mm+MIIID, 2.75mm+MIIB, 2.75mm+MIIC, 3.2mm+no injector. The patients averaged were 70±11, 68±11, 66±12, 69±10 years old. Intraocular pressure (IOP) was measured by Topcon CT80 pneumotonometer and corneal curvatures were measured by Topcon KR 8900 auto-refractor for all eyes. Preoperative axial length (AxL) and anterior chamber depth (ACD) were measured with Zeiss IOL Master in 2.2mm (cartridge D) and 2.75mm (cartridge C) groups. Postoperative corneal curvatures and IOP were measured at 1 day, 1 week, 1 month, and 3 months following surgery. All eyes underwent uneventful three planes coaxial micro incision cataract surgery (MICS) at superior limbus. The amount of the surgically induced astigmatism (SIA) was calculated by Alpin’s vector analysis method. Difference in SIA between various wound sizes was explored. Correlations between preoperative astigmatism, corneal curvatures, ACD, AxL, IOP, Age and SIA were analyzed for various wound sizes. In 2.2mm+MIIID group, the SIA was significantly smaller than those in 2.75mm+MIIC, 2.75mm+MIIB, and 3.2mm+no injector groups one week postoperatively. The SIA were 0.56±0.40 diopter (D), 0.71±0.68D, 0.75±0.54D, 0.80±0.63D one week postoperatively, and 0.5±0.45D, 0.58±0.55D, 0.52±0.41D, 0.54±0.33D three months postoperatively. 2.2mm+MIIID group had advantage in earlier stability of SIA and IOP after surgery. In addition to wound size, higher preoperative corneal astigmatism, older age, shallower ACD contributed to larger SIA for 2.2mm+MIIID and 2.75mm+MIIC groups. However, shorter AxL and lower IOP induced larger SIA in 2.75mm group, but not in 2.2 mm group. Therefore, decreasing limbal wound size and considering factors other than corneal astigmatism in predicting SIA could contribute to optimize refractive lens surgery.

並列關鍵字

Surgically Induced Astigmatism(SIA) ； diopter(D) ； intraocular pressure(IOP) ； anterior chamber depth(ACD) ； axial length(AxL) ； limbus

參考文獻

[1] Alpins. A new method of analyzing vectors for changes in astigmatism. J Cataract Refract Surg 1993; 19:524–533

[2] Alpins. Vector analysis of astigmatism changes by flattening, steepening, and torque. J Cataract Refract Surg1997; 23:1503–1514

[3] Alpins. New method of targeting vectors to treat astigmatism. J Cataract Refract Surg 1997; 23:65–75

[4] Alpins. et al, Astigmatism analysis by the Alpins method. ASCR and ESCRS, 2001

[6] Ahmed. et al, Biomechanical properties of human and porcine corneas. Experimental Eye Research 86, 2008

國際替代計量

白內障手術傷口大小及眼球結構對手術誘發散光之研究

全文下載

主題瀏覽